All the data so far shows the vaccines are highly effective at preventing serious disease or hospitalization, Dr. Anthony Fauci said. Vaccination is also imperative to preventing mutations, he added.

Transcript

MARY LOUISE KELLY, HOST:

Just before the fireworks, President Biden strolled onto the South Lawn to mark the Fourth of July with a speech. Hundreds of people were gathered - big Independence Day celebration. And Biden said the country is, quote, "closer than ever to declaring our independence from" the coronavirus. Maybe. It also seems like the road ahead could still be a long one, with the Delta variant now the dominant strain of the virus in the U.S. and mounting questions over how effective current vaccines are against it. Well, I'm joined by someone who can help us tackle some of those questions - the president's chief medical adviser. Dr. Anthony Fauci, welcome back.

ANTHONY FAUCI: Thank you. Good to be with you.

KELLY: So some of these questions are being prompted, as you know, by new data out of Israel suggesting the protection provided by the Pfizer vaccine may be waning, that its efficacy at preventing infection or symptomatic disease has dropped to 64%. A key caveat, which I'll say right at the top - they do still think the shot is highly effective at preventing serious disease or preventing death. But what is your read on this and these questions? Do the vaccines still work against this new variant?

FAUCI: Well, yeah. The answer, Mary Louise, is yes, it does if you look at the vaccines that we've been using here. And multiple studies from multiple countries show a high degree of efficacy, as you mentioned correctly, especially against severe disease leading to hospitalization. If you look at the effect against just infection itself or mildly symptomatic infection, the levels that we are getting in other studies seem to be substantially higher than the Israeli level of 64%. So what we really need to do before we can really make any determination is to get a bit more information from our Israeli colleagues, which we're trying to do. I have no doubt....

KELLY: So are you skeptical of the data out of Israel or just...

FAUCI: No, no, no, no, no, not at all. I have...

KELLY: Does it outlie or what?

FAUCI: No, no. I have a great deal of confidence in them. But before we try to extrapolate for the situation here, I would want to see a little bit more details of the data. The good news is that no matter what study you look at, the protection against severe disease leading to hospitalization is always well within the 90%, regardless of the study, regardless of the country.

KELLY: And I saw some of the news out of the White House COVID briefing today that here in the U.S., 99.5% of deaths from COVID are in...

FAUCI: Right.

KELLY: ...Unvaccinated people. It does suggest strongly that the vaccinations are working at preventing illness.

FAUCI: Yes. Very much so, Mary Louise. The data are so clear. And if you look in our own country, where the level of vaccination is low, the level of infection is increasing - and with that, you'll have hospitalizations. And hopefully not, but likely, you would see increase in deaths - an overwhelming reason why we've got to get as many people vaccinated as we possibly can.

KELLY: Are we also seeing more evidence that you really need to get both doses if what you're getting is a two-dose vaccine like Pfizer or Moderna?

FAUCI: Overwhelmingly, yes. We're seeing that in any study you look at. The level of protection when you follow one dose versus the level of protection following two doses is dramatically lower. People who feel, well, I've had one dose; do I really need the second dose - if you have a two-dose regimen, it is absolutely essential that you get your second dose.

KELLY: Let me turn this to masking. Los Angeles recently began encouraging even vaccinated people to mask indoors. The California state Capitol just laid down a mask mandate for lawmakers and staff because four fully vaccinated people there tested positive for the virus. Where are we on that? Should local officials in other parts of the U.S. be thinking about, OK, maybe we need to go back to mandating masks?

FAUCI: Well, from the standpoint of - let's take the CDC recommendations that if you are fully vaccinated, you have a high degree of protection. So the recommendation remains that you don't need a mask whether you're indoors or outdoors if you are fully vaccinated. The situation becomes a bit more complicated when you're in an area where you have two things - a low level of vaccination in the community and a high level of viral dynamics.

Under those circumstances, you could understand how some local authorities may say, you know, you might want to make sure you get the extra added benefit of having a mask. Although that is not a CDC recommendation, it is something that some people are considering, particularly the elderly and those who might have an underlying condition where they're not absolutely sure that they have an optimal immune response.

KELLY: OK. It's tricky because it's easier (laughter) just to say yes or no, you need it or you don't.

FAUCI: Exactly.

KELLY: This is more nuanced.

FAUCI: And that's the point. You know, there's a lot of variability among people in their own response and where they are and what their exposure is.

KELLY: How worried are you that the Delta variant could mutate into something more aggressive, more worrisome, particularly with so many unvaccinated people still out and about?

FAUCI: Well, that is a concern, Mary Louise. And that's the reason why we keep pushing, saying, please, people, if you're not vaccinated, seriously consider it; it's so easy to get vaccinated. Viruses don't mutate if they can't replicate, and you can prevent them from replicating by vaccinating enough people so that the virus has nowhere to go.

KELLY: Yeah.

FAUCI: If you give the virus free reign to circulate in the community, sooner or later it's going to mutate, and one of those mutations may be a mutation that makes it a more dangerous virus.

KELLY: And in this case, like with the Delta variant that's now the dominant one here, we've established it's more contagious. Do we know it actually causes more severe illness if you do catch it?

FAUCI: The data on the degree of transmissibility is very clear. There's no doubt it's more transmissible. It is likely when you get more data that it is likely that it also can give you a more serious disease.

KELLY: Last thing, and this is back to masking because so many people look to you as the guide to how to navigate this - are you wearing a mask any more in any circumstances?

FAUCI: You know, personally, I don't for the simple reason that my environment, Mary Louise, is so restricted. I spend very little time with people who are not vaccinated. So it isn't as if I'm out and about out there, intermingling in places where there's a lot of infection. So for that reason, very unusual for me to wear a mask.

KELLY: If you were headed to a crowded concert indoors in a state where the case rates are still high, would you think about it?

FAUCI: You know, being an 80-year-old person, Mary Louise, I would seriously think about that. Yes.

KELLY: Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and chief medical adviser to the president. Thank you so much. Good to speak with you again.

FAUCI: Thank you for having me.

ARI SHAPIRO, HOST:

And some news broke this evening after we spoke with Dr. Fauci. Pfizer announced a third booster shot of its vaccine could help protect people against the Delta variant. The company plans to ask the FDA for emergency authorization. Transcript provided by NPR, Copyright NPR.